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A clinical score to identify patients at risk of severe asthma flare-ups

Published Online: September 23, 2014

A major goal of asthma management is to prevent severe asthma flare-ups (also called severe exacerbations). Although regular controller treatment reduces this risk, some patients remain at high risk. Identifying such patients in advance may assist physicians in deciding when to change treatments, and in selecting options that are more effective in preventing these serious and even life-threatening events. Several measures, both simple and complex have been proposed for predicting the course of disease and future events. In a study recently published in The Journal of Allergy and Clinical Immunology (JACI), Bateman and colleagues aimed to develop and validate a novel, numeric risk score for asthma exacerbation (RSE) that may be used by clinicians to manage patients with moderate or severe asthma and by researchers to compare the ability of different treatments to prevent exacerbations.

Bateman et al. analyzed a database of 7,446 patients who had taken part in one of three large asthma trials. Patients were identified as being at risk of an exacerbation using exacerbation history within the previous year and current frequent symptoms of asthma. The studies compared the efficacy of different treatment options for reducing asthma exacerbations: inhaled corticosteroids (ICS) alone, combination therapy with an ICS and a long-acting beta2-agonist (LABA), or the combination of the ICS, budesonide, with the rapid-onset LABA, formoterol, both as controller (regular use) and as reliever (prompted by breakthrough symptoms of asthma). Multivariate analysis of demographic and clinical features at baseline confirmed differences between factors that predicted failure to achieve satisfactory asthma control at three months on current study treatments, and risk of an exacerbation requiring oral corticosteroids, emergency department treatment, or hospitalization over the next 6 to 12 months.

The five most predictive factors of an exacerbation were the patient’s Global Initiative for Asthma treatment step (based on controllers currently in use; Step 4 versus Step 3), frequency of reliever use for symptoms, post-bronchodilator forced expiratory volume in 1 second, the 5-item Asthma Control Questionnaire score, and Body Mass Index. The contribution of each risk factor was weighted to develop the RSE, and the RSE was validated in a second cohort of participants from the same clinical trials.

The RSE ranges from 0 (an approximately 5% risk of an asthma exacerbation during the next 6 months) to 100 (approximately 40% risk). Management guidelines recommend that recognition of high risk should prompt clinicians to review modifiable risk factors and current treatment. Bateman et al. observed that actual exacerbation rates for corresponding RSE values were consistently lower with treatments known to be more effective in reducing exacerbation risk. Thus, budesonide/formoterol used both as maintenance and reliever was associated with lower rates of exacerbations across all RSE scores, and increasingly in those at higher risk. The RSE needs to be validated in further cohorts of patients with asthma of varied severity and receiving different treatments.

The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.